Takes a long time to return to Idle

[philzphly]

Looking for some diagnostic help.

I'll give the backstory first and then where I'm at. any advice or thoughts whould be helpful.

Had the bike for a couple of months, third owner. 97 GS 500. Been dropped 4 times standing still. twice first owner twice second owner.

Had friend go over the bike and do basic stuff. new tires, oil etc.

A few weeks ago was driving along and heard a POP. almost sounded like a backfire and then a spring popping . Then the Idle was all off. and suddenly the engine was acting strange. After releasing the throttle the engine would either take a lot longer to go back to idle like a good 3-5 seconds to go from 6000 rpm to 1200 rpm or it would stay up at 5-6000 rpm. If I was in gear and let the clutch out a little sometimes it would then go back to idle.

I took the bike into the shop and just told them it needed maintenance. and carb cleaned. I told them the idle was off. Finally got the bike back and in some ways it was running smoother but still has the long return to idle. After talking to them for a while they said it sounds like the diaphram on the carbs might be tight (stiff). They offered to have me leave it or they could check it out more. I'm not worried about them taking me for a ride as a) I was not specific on part of the problem and b) they had done work so i knew aspects of the bike were running better. I decided to ride the bike around some to see if it settles back to normal with some of the work they've done (carb clean, lubricating the throttle cable) and I may take them up on their offer and bring it back. But I would like to get some feedback.

I know the bike had a significant life outdoors, had alot of rust on the bolts etc, was housed near a damp area of nyc (somewhat close to the hudson river)

Any thoughts. It is ridable and fine while cruising. seems to run hotter than it did before, and as i said it goes back and forth between staying at a higher rpm, taking a long time to return to idle, and going back to idle normally.

Thanks for any insight anyone has.

Philippe

[Jared]

Slow return to idle is a lean condition....So is running Hot.  Your pilot Jets are likely clogged somewhat  or you have an air leak somewhere. One of the  little o-rings in the carb tops may be missing or something .

Do a search...you'll find quite a few messages dealing with this.

[RVertigo]

Sticky throttle cable?

[Jared]

He said they lubed the throttle cable. Hanging RPM's like that is almost always a lean condition.

[RVertigo]

He said they lubed the throttle cable.

Sorry... I don't know how to read.

[philzphly]

I ran it around the block a few times.

I'm hearing pop sounds too. Almost backfiring.

It seems to be all over the place. sometimes it revs to 4-6k clutch in, in first gear I've been trying some engine braking. sometimes it'll drop the rpm's sometimes it stays high. If I pull up to a stop  (clutch in, in first) and it's reving sometimes If I let off the clutch a little while holding the bike in place with my feet, it will drop.

I'm going to try and grab someone to check it over with me beforei go back to the shop.

[Larry]

You need to rule out a simple air leak that may be causing the GS to run lean.  While running at idle spray some WD-40 on the carb boot connections.  If the idle jumps up you are sucking air (the WD-40 burns like a fuel).  I found my carb boots need to be tighter and that solved my idle problem.

[rritterson]

are you sure the choke (actually fuel enrichment) system is working properly? Also, I'm sure you've already checked it out, but maybe the idle adjust screw popped loose and is now far away from where it should be set.

[philzphly]

I did the wd-40 test and no change in idle.

The idle goes back and forth. I have become intimately aquainted with it's location. When the engine is cold sometimes i tweak the idle up. Once the engine is warmed up (or hot) i tweak it back down.

If I understand a lean condition (in general terms) that the engine is getting too much air, then I'm assuming there's either an air leak that the wd-40 didn't or something in the mechanism that is inconsistently letting too much air in sometime and seems to be fine other times.

[sellis]

Going back to what rritterson said, check to make sure that the choke cable is actually moving the choke lever on the carb. Obviously I am not a mechanic or I would use the actual part names, but I did have a similar rpm problem with it not idling properly. The bike would also rev higher and I could never get the idle properly set. We took off the choke cable and lubed it and it works fine now. We just sprayed generous amounts of WD-40 in it and worked the cable back and forth a few (hundred) times.
Sam

[philzphly]

I'm going to get help to try the Chake cable.

I am starting to think it might be multiple isses which can only mean take one at a time.

For further clues. I've noticed a little sound, like a click or "tink" when the the reving goes from being more normal to being more constant. It'll be fine then "tink" and it speeds up or it's on fast and constant and "tink" it goes back towards normal.

The problem seems to be MUCH more evident on and incline or decline.

I'll keep the board updated.

Thanks for everyone's help.

[philzphly]

That would be Choke cable...

[leolegend]

We addressed this problem recently on my friends bike.  Took apart the carbs and noticed that both o rings on each carb were shrunk and hard, replaced them and problem solved.  Also readjusted the floats.